Automatic selective needle pressure control



Aug. 22, 1961 H. H, MUELLER 2,997,305

AUTOMATIC SELECTIVE NEEDLE PRESSURE CONTROL Filed Jan. 6, 1958 Fig.

Herman H. Mueller 1 N VE N TOR.

l0 9 Mada.

2 BY v aw United States atent O 2,997,305 AUTOMATIC SELECTIVE NEEDLE PRESSURE CONTROL Herman H. Mueller, 123 W. King St., 'Ephrata, Pa.;

Elizabeth M. Mentzer, executrix of the will of Herman H. Mueller, deceased Filed Jan. 6, 1958, Ser. No. 704,044 13 Claims. (Cl. 274-23) This invention comprises a novel and useful automatic selective needle pressure control and comprises a continuation-in-part of my prior co-pending application Serial No. 674,118, filed July 25, 1957 for Mercury Needle Pressure Control for Tone Arm.

The subject matter disclosed in the present application, and in my above identified prior co-pending application specifically relates to a stylus and/or needle pressure mechanism adapted for use with record players of the type having tone arms tiltable from a neutral horizontal non-playing position both upwardly and downwardly about a centrally located fulcrum of the tone arm to thereby selectively play the underside and top sides of records either supported above or resting upon the turntable and driven thereby.

The present invention is similar in subject matter but constitutes an improvement on the tone arm counterbalancing mechanism disclosed in my prior Patent No. 2,809,841, granted on October 15, 1957 and as disclosed and claimed in my further prior Patent No. 2,809,842 granted on October 15, 1947 the latter patent comprising a division of my first mentioned patent.

The primary object of this invention is to provide a selective mercury needle pressure control mechanism for the tone arms which shall be of a simple, compact and efficient construction; may be readily applied to conventional tone arms of any suitable type; and shall be especially adaptable for use with the arms disclosed in my prior application Serial No. 598,473; and Patents No. 2,729,455, 2,809,841 and 2,809,842.

A further object of the invention is to provide a needle pressure mechanism wherein all parts of the same shall be disposed at the side of a tone arm and shall not extend above the upper surface of the same, to thereby offer no interference to movement of the tone arm and associated elements of a phonograph record player.

Another very important object of the invention is to provide a mercury needle pressure mechanism for tone arms wherein independently adjustable needle pressure weights for urging the arm upwardly or downwardly about a central fulcrum may be individually adjusted.

Yet another object of the invention is to provide a needle pressure control which may be automatically adjusted in synchronization with the positioning of a particular needle or stylus for playing a particular type of record, in order that when the needle or stylus is set to play a particular type of record an appropriate pressure may be automatically imposed upon the needle.

Yet another object of the invention is to provide a mechanism in accordance with the preceding objects wherein provision is made for individually adjusting each of the pressures applied to the upwardly and downwardly projecting needles; and which may be employed in conjunction with the previously mentioned adjustment of the needle pressure weight.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a top plan view, parts being broken away showing the manner in which the needle pressure mechanism of this invention has been applied to the side of a tone arm of the type having upward and downward tilting movement from a neutral non-playing position, about an intermediately disposed fulcrum for the tone arm- FlGURE 2 is a side elevational view of the arrangement of FIGURE 1;

FIGURE 3 is a vertical longitudinal sectional view taken on an enlarged scale substantially upon the plane indicated by section line 33 of FIGURE 2, parts being broken away, and showing in particular the automatic mechanism connected with the stylus adjusting means for simultaneously adjusting the needle pressure elements of the device;

FIGURE 4 is a vertical longitudinal sectional view taken substantially upon the plane indicated by the section line 4-4 of FIGURE 3, parts being broken away, and showing further details of the mechanism thereof;

FIGURE 5 is an exploded perspective view of a portion of the base plate and one of the adjustable mercury elements of the device; and

FIGURE 6 is a vertical transverse sectional detail view taken substantially upon the plane indicated by the section line 66 of FIGURE 4.

Indicated generally by the numeral 10 is a tone arm which is of a type adapted to have vertical tilting movement about a fulcrum disposed intermediate the ends of the arm as by means of fulcrum pivot pins 12 which connect the sides 14 and 16 of the tone arm to the upstanding arms 18 of a support bracket designated generally by the numeral 19, the arms of the bracket being received within the two tone arm sides as shown best in FIGURE 3, the bracket being carried by a support post 20 by which the tone arm may be vertically lifted or lowered and may be oscillated or swung horizontally during operation of a conventional form of record player.

The mechanism for imparting upward and downward tilting movement to the tone arm may be of any suitable construction, and since the principles of the present invention are not limited thereto, and since this mechanism is well understood by those skilled in the art, and a suitable form of the same has been disclosed in my above-mentioned patent, illustration and explanation of the same is deemed to be unnecessary herein.

The tone arm is provided with a needle or stylus assembly, the same including an upwardly projecting needle 24 and a downwardly projecting needle 26, these needles being adapted to play respectively the underside of a record supported above a turntable and driven thereby and the top side of a record supported upon a turntable and rotatable therewith. As shown in FIGURE 1, a plurality of sets of these oppositely disposed needles are provided, each set being adapted to play a certain type of record. Since a suitable type of needle assembly for this purpose has been disclosed and claimed in my prior Patent No. 2,809,842 granted on October 15, 1957 a further description of the same is deemed to be unneces-.

sary for the purposes of this invention. It will of course be understood that the tone arm includes the usual mechanism connected with the needle for transmitting electrical impulses to the sound reproductive mechanism of the record player.

The selective needle pressure control mechanism of this invention is mounted upon the side of the tone arm 10 and enables the pressure of the needles 24 and 26 to be independently respectively adjusted when they rest upon or in the sound track of the underside or top side of records depending upon the direction of tilting of the tone arm from a neutral non-playing position thereof.

Referring especially to FIGURE 5 it will be seen that there is provided a flat T-shaped plate designated gener-' a a tud'inally extending portion 32 adapted to rest against the side of the tone arm, and a depending stern portion 34 depending medially from the upper portion. The plate 32 is secured to the side of the tone arm in any suitable manner as by fastening screws, not shown. The base plate serves as a means to support for adjustable movement either automatic or manual or both a pair of mercury weight members by which adjustable pressure is imparted to the tone arm and through the later to the upper or lower needles 24, 26 respectively as desired by means to be subsequently set forth.

Disposed within the tone arm is a transverse web or partition 36 in which is journalled a sleeve 38 having a cam 40 secured thereto and abutting against the partition 30, this sleeve being retained rotatably in the partition as by a collar 42 on the other side of the same. A flexible housing 44 having therein a flexible operating cable 46 is operatively connected whereby rotation of the cable 46 will cause rotation of the sleeve 38 and the cam 40, and also through a manual clutch assembly 48 mounted in the tone arm, will impart rotation to a spindle 50 forming a part of the needle or stylus assembly.

The cable 46 is operatively connected to a suitable control mechanism such as that disclosed in my prior applicaiton Serial Nos. 347,507, filed April 8, 1953 and by means of which when the speed at which a turntable is driven is varied in accordance with the record to be played will also result in adjusting the stylus assembly to position the proper or appropriate set of needles for that speed. By means of the present invention, the cam 40 in turn adjusts the mercury weight so that the desired pressure may be applied to the selective needle for most effective operation of the same.

Referring now more particularly to FIGURES 3-5, it will be seen that the fulcrum pin 12 previously mentioned is adapted to extend through aligned apertures in the bracket arm 18, the side 14 of the tone arm, a centrally disposed aperture 54 in a bent lever 56, and a corresponding aperture 58 in the upper portion 32 of the base plate 30. The upper end of this lever 56 as set forth hereinafter is operatively connected to the cam 40 whereby an oscillatory movement is imparted to the lever Wlen the needle assembly is adjusted through the cable 4 'Below the aperture 58, the horizontal portion 32 of the base plate 30 is provided with a concentric arcuate slot 60 through which is movable a crank pin 62 carried by the lower end of the lever 56. This pin extends to the exterior of the tone arm, travelling in a corresponding arcuate slot therein, and has pivotally connected thereto one end of each of a pair of connecting links 64 and 66, see FIGURE 3 in particular. Each of the links in turn is apertured as at 68 for engagement upon a pin 70 carried by the lower depending portion 72 of each of a pair of plates 74 comprising tilting members. part of the depending portion 72 of each tilting member is provided with an aperture 76 registering with an aperture 78 on the depending portion 34, for the engagement of bolts 80 which constitute pivots or fulcrums for the tilting members. These bolts are preferably threaded into the aperture 78 so that tilting or pivotal movement may be given to the tilting members or plates as set forth hereinafter, or these plates will be locked against tilting movement, in a selected adjustment position of the mercury weights carried by the tilting plates when it is desired to manually adjust the same and dispense with the automatic operating mechanism of the mercury weight tilting means.

Secured to each of the tilting members 74 as by a clamp 82 and a fastening screw 84 constituting a pivot pin is a horizontally elongated mercury tube 86. The tube projects outwardly beyond the end of the tilting plate as shown clearly in FIGURE 5 and adjacent its outer end is surrounded by a metallic band 88 comprising an adjusting or thrust means.

The lowermost Secured to both the top and underside of the tone arm are a pair of laterally projecting brackets 90 disposed above the tone arm and 92 disposed therebeneath. Screw threadedly engaged in these brackets are adjusting screws 94 adapted to respectively engage the upper or lower portions of the bands 88 to thereby limit upward and downward tilting of the mercury weight tubes 86 about their pivots 84.

The mercury tubes along their length are tapered and provided with longitudinally spaced depressed portions 96. These portions are of progressively greater depth from the outer ends of the tubes toward their pivot point and comprise reservoirs or pockets for receiving a quanti-ty of mercury disposed within the tubes. These pockets are so arranged that for a given inclination of the tube, the mercury will rest in one of the depressions. Progressive further downward tilting of the tube 86 about the pivot 89 will cause the mercury to move progressively toward the outer and lower end of the tube, thereby increasing the weight on the tone arm at either side of the pivots 12 and thereby increasing the weight on a selected needle 24 or 26.

In the position of the parts shown in FIGURES 2 and 4, which is the neutral position of the tone arm, the lower sides of the mercury tube are slightly inclined from their outer ends toward the innermost depression or reservoir whereby mercury under the influence of gravity will tend to collect in the reservoir. However, upon a very slight tilting movement of the tube, either by adjustment of the tilting members through the thumb screws 94 hearing against the bands 88, or by tilting of the tilting plates 74 through the lever 56 and the links 64 and 66 by a means to be subsequently set forth, the mercury weight will run towards or from the upper end of the tubes thereby varying the lever arm of the mass of mercury by which a tilting force is applied to the tone arm to urge the corresponding needle 24 or 26- against the sound track of its record with a predetermined adjustable pressure.

Referring now especially to FIGURES 3, 4 and 6, it will be observed that the cam disk 40 has upon one face thereof a circumferentially extending cam surface 109. Cooperating with this cam surface is a cam follower 192 having a bifurcated extremity 164 in which is a journalled a roller 1126 which rides upon the cam surface. At its opposite end from the bifucated end, the cam follower 102 has an internally threaded bore 108 in which is disposed the externally threaded extremity 110' of a rod 112, whereby relative adjustment between these members is effected, a lock nut 114 being provided for maintaining the screw threaded adjustment therebetween.

The follower 102 is slidingly guided in a guide bracket 116, and a similar guide bracket 118 is provided for the rod 112. These guide brackets are secured to the side 14 of the tone arm.

A compression spring 120 encircles the rod 112, abutting against the -bracket 118 and against the adjusting nut 114, to thereby yieldingly urge the roller 106 against the cam surface 100.

At its outer end, the rod 112 has a bifurcated extremity 122 which is pivotally connected at 124 to the apertured upper end 126 of the previously mentioned lever 56. It will thus be apparent that when the cable 46 is rotated in order to adjust the needle assembly, it will also impart rotation to the cam plate 40, and through the cam surface 100 will cause the spring urged follower 102 to move inwardly or outwardly depending upon the position of the cam wheel 106 on the cam surface 100. This horizontal sliding movement of the rod 112 in turn will actuate the lever 56 and through the latter will impart reverse tilting movement to the mercury tubes 86. One tube will be tilted upwardly, causing its mercury to run toward the center, while the other tube will be tilted downwardly causing its mercury to move outwardly toward its end and thereby increase the lever arm of the mercury weight therein, the extent of tilting of the two tubes being of course limited by adjustment of the screws 94 at the top and bottom sides of each tube.

In some instances, it may be preferred to omit the automatic actuating means for the mercury weights, and to rely solely upon manual adjustment for the same. This manual adjustment can of course be effected by loosening the locking pivot screws 80, tilting the plates 674 into the desired angular position to effect a desired adjusted pressure upon the tone arm and a particular needle or stylus, and lock the plates in that position by the screws 89.

The previously mentioned clutch assembly 48 is provided with a manually operated knob or button 49 slidably disposed on the top of the tone arm as shown in FIGURES 1 and 2. By means of this knob, the clutch 48 may be selectively actuated to connect or disconnect the needle assembly from the automatic actuating means therefor. When the clutch is disengaged, the cable 46 will no longer automatically change the needle assembly and actuate the adjustable needle pressure mechanism in conjunction with the changing of the turntable speed; but the needle assembly will be manually adjustable.

It will be observed that the needle pressure control disclosed herein obviates the use of springs in adjusting the pressure upon a needle or in tilting the tone arm in either direction. Further, the same mechanism which adjusts the turntable speed for playing a particular record also simultaneously selects and positions the proper needle and applies the proper pressure to the needle.

Shown at 130 is a counterweight disposed on the tone arm at the opposite side of the fulcrum pin 12 by the stylus assembly. This counterweight may be longitudinally adjusted upon the tone arm in any desired manner in order to impart any selected balance or vertical bias either upwardly or downwardly to the tone arm.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A needle pressure control mechanism for a tone arm of the type having an adjustable needle assembly with a plurality of sets of upwardly and downwardly projecting needles and a fulcrum for said tone arm whereby the latter may be tilted from a neutral non-playing position to upwardly or downwardly tilted playing positions; and mechanism comprising a pair of needle pres sure weights, means mounting said weights upon said tone arm for effect upon opposite sides of said fulcrum, said mounting means including means varying the center of gravity of at least one weight from said fulcrum, means connecting said varying means to said adjustable needle assembly for applying thereby a predetermined effective force to said tone arm for a selected set of upwardly and downwardly projected needles, means for actuating said varying means independently of actuation of the latter by said connecting means.

2. A needle pressure control mechanism for a tone arm of the type having an adjustable needle assembly with a plurality of sets of upwardly and downwardly projecting needles and a fulcrum for said tone arm whereby the latter may be tilted from a neutral non-playing position to upwardly or downwardly tilted playing positions; and mechanism comprising a pair of needle pressure weights, means mounting said weights upon said tone arm for effect upon opposite sides of said fulcrum, said mounting means including means varying the center of gravity of at least one weight from said fulcrum, means connecting said varying means to said adjustable needle assembly for applying thereby a predetermined effective force to said tone arm for a selected set of upwardly and downwardly projected needles, stop means carried by said tone arm cooperating with said mounting means for adjustably limiting the movement of the center of gravity of said one weight relative to said fulcrum.

3. A needle pressure control mechanism for a tone arm of the type having an adjustable needle assembly with a plurality of sets of upwardly and downwardly projecting needles and a fulcrum for said tone arm whereby the latter may be tilted from a neutral non playing position to upwardly or downwardly tilted playing positions; and mechanism comprising a pair of needle pressure Weights, means mounting said weights upon said tone arm for effect upon opposite sides of said fulcrum, said mounting means including means varying the center of gravity of at least one weight from said fulcrum, means connecting said varying means to said adjustable needle assembly for applying thereby a predetermined effective force to said tone arm for a selected set of upwardly and downwardly projected needles, said weights comprising mercury tubes and a quantity of mercury movable in said tubes.

4. A needle pressure control mechanism for a tone arm of the type having an adjustable needle assembly with a plurality of sets of upwardly and downwardly projecting needles and a fulcrum for said tone arm whereby the latter may be tilted from a neutral non-playing position to upwardly or downwardly tilted playing positions; and mechanism comprising a pair of needle pressure weights, means mounting said weights upon said tone arm for efiect upon opposite sides of said fulcrum, said mounting means including means varying the center of gravity of at least one weight from said fulcrum, means connecting said varying means to said adjustable needle assembly for applying thereby a predetermined effective force to said tone arm for a selected set of upwardly and downwardly projected needles, said weights comprising mercury tubes and a quantity of mercury movable in said tubes, said tubes including a plurality of pockets therein disposed at different distances from said fulcrum and being so disposed that the mercury will be successively displaced from pocket to pocket in accordance with progressive changes in the inclination of the tubes.

5. A needle pressure control mechanism for a tone arm of the type having an adjustable needle assembly with a plurality of sets of upwardly and downwardly projecting needles and a fulcrum for said tone arm whereby the latter may be tilted from a neutral non-playing position to upwardly or downwardly tilted playing positions; said mechanism comprising a pair of needle pressure weights, means mounting said weights upon said tone arm for effect upon opposite sides of said fulcrum, said mounting means including means varying the center of gravity of said weights from said fulcrum, means connecting said varying means to said adjustable needle assembly for applying thereby a predetermined effective force to said tone arm for a selected set of upwardly and downwardly projected needles said connecting means including a lever pivoted to said tone arm upon the interior thereof, an operating means connecting said lever to said needle assembly and further means connecting said later to said weight varying means.

6. The combination of claim 7 wherein said connecting means includes a lever pivoted to said tone arm upon the interior thereof, an operating means connecting said lever to said needle assembly and further means connecting said lever to said weight varying means.

7. In a tone arm having a changeable needle assembly comprising a plurality of sets of needles, each set having a pair of upwardly and downwardly projecting needles for respectively engaging the bottom and top sides of records supported and driven aboye and upon a turntable, said sets of needles being adapted for engaging different types of records, means in said tone arm for actuating said needle assembly to position a selected set of needles in operative position; a needle pressure control mechanism comprising a pair of needle pressure weights, means mounting each weight upon said tone arm upon one side of the latter for movement longitudinally of the tone arm whereby to vary the pressure imposed by said tone arm and weight upon a needle engaging a record, means conmeeting said pressure weights to said actuating means for rendering efiective that weight which is positioned for increasing the pressure of the tone arm upon the needle selectively positioned for operation by said actuating means.

8. In a tone arm having a changeable needle assembly comprising a plurality of sets of needles, each set harn'ng a pair of upwardly and downwardly projecting needles for respectively engaging the bottom and top sides of records supported and driven above and upon a turntable, said sets of needles being adapted for engaging different types of records, means in said tone arm for actuating said needle assembly to position a selected set of needles in operative position; a needle pressure control mechanism comprising a pair of needle pressure weights, means mounting each weight upon said tone arm upon one side of the latter for movement longitudinally of the tone arm whereby to vary the pressure imposed by said tone arm and weight upon a needle engaging a record, means connecting said pressure weights to said actuating means for rendering effective that weight which is positioned for increasing the pressure of the tone arm upon the needle selectively positioned for operation by said actuating means, said actuating means including a shaft rotatably mounted in said tone arm and secured to said needle assembly, said connecting means being connected to said shaft.

9. In a tone arm having a changeable needle assembly comprising a plurality of sets of needles, each set having a pair of upwardly and downwardly projecting needles for respectively engaging the bottom and top sides of records supported and driven above and upon a turntable, said sets of needles being adapted for engaging difierent types of records, means in said tone arm for actuating said needle assembly to position a selected set of needles in operative position; a needle pressure control mechanism comprising a pair of needle pressure weights, means mounting each weight upon said tone arm upon one side of the latter for movement longitudinally of the tone arm whereby to vary the pressure imposed by said tone arm and weight upon a needle engaging a record, means connecting said pressure Weights to said actuating means for rendering effective that weight which is positioned for increasing the pressure of the tone arm upon the needle selectively positioned for operation by said actuating means, said needle assembly including a shaft rotatably mounted in said tone arm, said connecting means including a cam on said shaft, a rod guided in said tone arm for sliding movement and having one end engaging said cam and having its other end connected to said pressure weights.

10. In a tone arm having a changeable needle assembly comprising a plurality of sets of needles, each set having a pair of upwardly and downwardly projecting needles for respectively engaging the bottom and top sides of records supported and driven above and upon a turntable, said sets of needles being adapted for engaging different types of records, means in said tone arm for actuating said needle assembly to position a selected set of needles in operative position; a needle pressure control mechanism comprising a pair of needle pressure weights, means mounting each Weight upon said tone arm upon one side of the latter for movement longitudinally of the tone arm whereby to vary the pressure imposed by said tone arm and weight upon a needle engaging a record, means connecting said pressure weights to said actuating means for rendering etfective that weight which is positioned for increasing the pressure of the tone arm upon the needle selectively positioned for operation by said actuating means, said mounting means including a base plate secured to the side of a tone arm, a pair of adjusting plates, each pivoted to said base plate, said connecting means being connected to said base plates for effecting pivotal movement thereof.

11. The combination of claim 10 wherein said pressure Weights include mercury tubes secured to said adjusting plates.

12. The combination of claim 11 wherein said mercury tubes have progressively outwardly spaced lower depressions for retaining therein the mercury weight at diiierent distances from the pivot of said adjusting plates for different inclinations of the latter.

13. The combination of claim 12 including stop means on said tone arm limiting tilting of said adjusting plates.

References Cited in the file of this patent UNITED STATES PATENTS 2,356,467 Martin Aug. 22, 1944 2,526,188 Andres Oct. 17, 1950 2,568,671 Vistain Sept. 18, 1951 2,601,126 Palo June 17, 1952 2,608,411 Fisher Aug. 26, 1952 2,729,455 Mueller Jan. 3, 1956 2,809,841 Mueller Oct. 15, 1957 

